30 lines
658 B
Plaintext
30 lines
658 B
Plaintext
import type {IfEmptyObject} from './if-empty-object';
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import type {IsUnion} from './internal';
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/**
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Create a type that only accepts an object with a single key.
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@example
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```
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import type {SingleKeyObject} from 'type-fest';
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const someFunction = <T>(parameter: SingleKeyObject<T>) => {};
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someFunction({
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value: true
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});
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someFunction({
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value: true,
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otherKey: true
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});
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// Error: Argument of type '{value: boolean; otherKey: boolean}' is not assignable to parameter of type 'never'.ts(2345)
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```
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@category Object
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*/
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export type SingleKeyObject<ObjectType> =
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IsUnion<keyof ObjectType> extends true
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? never
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: IfEmptyObject<ObjectType, never, ObjectType>;
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